
<h1><span class="yiyi-st" id="yiyi-12">numpy.flatnonzero</span></h1>
        <blockquote>
        <p>原文：<a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.flatnonzero.html">https://docs.scipy.org/doc/numpy/reference/generated/numpy.flatnonzero.html</a></p>
        <p>译者：<a href="https://github.com/wizardforcel">飞龙</a> <a href="http://usyiyi.cn/">UsyiyiCN</a></p>
        <p>校对：（虚位以待）</p>
        </blockquote>
    
<dl class="function">
<dt id="numpy.flatnonzero"><span class="yiyi-st" id="yiyi-13"> <code class="descclassname">numpy.</code><code class="descname">flatnonzero</code><span class="sig-paren">(</span><em>a</em><span class="sig-paren">)</span><a class="reference external" href="http://github.com/numpy/numpy/blob/v1.11.3/numpy/core/numeric.py#L803-L840"><span class="viewcode-link">[source]</span></a></span></dt>
<dd><p><span class="yiyi-st" id="yiyi-14">在a的扁平版本中返回非零的索引。</span></p>
<p><span class="yiyi-st" id="yiyi-15">这相当于a.ravel()。nonzero()[0]。</span></p>
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<tr class="field-odd field"><th class="field-name"><span class="yiyi-st" id="yiyi-16">参数：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-17"><strong>a</strong>：ndarray</span></p>
<blockquote>
<div><p><span class="yiyi-st" id="yiyi-18">输入数组。</span></p>
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<tr class="field-even field"><th class="field-name"><span class="yiyi-st" id="yiyi-19">返回：</span></th><td class="field-body"><p class="first"><span class="yiyi-st" id="yiyi-20"><strong>res</strong>：ndarray</span></p>
<blockquote class="last">
<div><p><span class="yiyi-st" id="yiyi-21">输出数组，其包含非零的<em class="xref py py-obj">a.ravel()</em>的元素的索引。</span></p>
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<div class="admonition seealso">
<p class="first admonition-title"><span class="yiyi-st" id="yiyi-22">也可以看看</span></p>
<dl class="last docutils">
<dt><span class="yiyi-st" id="yiyi-23"><a class="reference internal" href="numpy.nonzero.html#numpy.nonzero" title="numpy.nonzero"><code class="xref py py-obj docutils literal"><span class="pre">nonzero</span></code></a></span></dt>
<dd><span class="yiyi-st" id="yiyi-24">返回输入数组的非零元素的索引。</span></dd>
<dt><span class="yiyi-st" id="yiyi-25"><a class="reference internal" href="numpy.ravel.html#numpy.ravel" title="numpy.ravel"><code class="xref py py-obj docutils literal"><span class="pre">ravel</span></code></a></span></dt>
<dd><span class="yiyi-st" id="yiyi-26">返回包含输入数组元素的1-D数组。</span></dd>
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<p class="rubric"><span class="yiyi-st" id="yiyi-27">例子</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">x</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">arange</span><span class="p">(</span><span class="o">-</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">x</span>
<span class="go">array([-2, -1,  0,  1,  2])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">np</span><span class="o">.</span><span class="n">flatnonzero</span><span class="p">(</span><span class="n">x</span><span class="p">)</span>
<span class="go">array([0, 1, 3, 4])</span>
</pre></div>
</div>
<p><span class="yiyi-st" id="yiyi-28">使用非零元素的索引作为索引数组来提取这些元素：</span></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">x</span><span class="o">.</span><span class="n">ravel</span><span class="p">()[</span><span class="n">np</span><span class="o">.</span><span class="n">flatnonzero</span><span class="p">(</span><span class="n">x</span><span class="p">)]</span>
<span class="go">array([-2, -1,  1,  2])</span>
</pre></div>
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